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arXiv 0901.4105hep-phhep-ex
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LHC上的Squark Flavor违规

Squark Flavor Violation at the LHC

Graham D. Kribs, Adam Martin, Tuhin S. Roy

摘要:

我们认为,通过在大型强子对撞机单顶生产的信号测量夸克味违反的前景。我们在R-对称超对称的背景下研究这个信号,它允许在squark扇区中有大的味道违反,但是结果也可以推广到MSSM。单顶信号来自夸克对的产生,其中一个夸克衰变为顶夸克和高吉诺,而另一个夸克衰变为非顶夸克和高吉诺。我们研究了三种衰变模式:(I)夸克衰变为夸克和中性伴子LSP;(II)夸克衰变为夸克和中性伴子NLSP,随后NLSP衰变为光子和引力伴子;(III)夸克衰变为夸克和电荷伴子NLSP,随后NLSP衰变为H^ \pm /W^ \pm和引力伴子。第二种情况是最有希望的,当NLSP衰变是即时的,因为每个事件都包含两个硬光子,可以用来标记事件,将背景降低到可以忽略的水平。如果中性伴子LSP是类双星的,则情况I是有希望的。我们仔细考虑了大的SM背景,并确定了一系列的削减,以隔离信号。第三种情况可能发生在MRSSM中,具有Higgsino样最轻的gauginos。由于大的希格斯耦合,方夸克优先衰变为顶夸克,大大减少了潜在的味道违反信号。然而,如果电荷NLSP是长寿命的,则风味违反信号可能仍然是可识别的。

英文摘要:

We consider the prospects for measuring squark flavor violation through the signal of single top production at the LHC. We study this signal in the context of R-symmetric supersymmetry, which allows for large flavor violation in the squark sector, however the results can also be generalized to the MSSM. The single top signal arises from squark pair production in which one squark decays to a top and gaugino, whereas the other squark decays to a non-top quark and gaugino. We study three decay patterns: (I) squark decay into a quark and neutralino LSP; (II) squark decay into a quark and neutralino NLSP, with subsequent decay of the NLSP to a photon and gravitino; (III) squark decay into a quark and chargino NLSP, with subsequent decay of the NLSP to a H^\pm/W^\pm and gravitino. Case II is the most promising, when the NLSP decay is prompt, since every event contains two hard photons that can be used to tag the events, reducing the background to a negligible level. Case I is promising if the neutralino LSP is bino-like. We carefully consider large SM backgrounds and identify a series of cuts to isolate the signal. Case III can occur in the MRSSM with Higgsino-like lightest gauginos. Due to the large Higgs coupling, squarks preferentially decay to top quarks, substantially reducing the potential flavor violating signal. Nevertheless, the flavor violating signal might still be identifiable if the chargino NLSP is long-lived.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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